The present invention relates to the manufacture of gypsum board panels, and more particularly, to a means by which the frequency of delamination of gypsum board paper during lamination of gypsum board panels can be greatly reduced.
Gypsum board panels, in their simplest form, consist of a thin, flat slab of gypsum sandwiched between layers of gypsum paper. Usually, one side of the panel is made with a light-colored, smoothly textured paper, which is referred to as the face paper or the manila paper layer. The other side of the panel is usually made with a darker, less smoothly-textured paper, which is referred to as the backing paper or the newslined paper layer.
For decorative purposes, various films are laminated to the face surface of gypsum board panels. In typical applications, the laminated boards are provided with an exterior pattern that resembles wallpaper. These laminated panels are used in the manufactured housing industry for making interior walls in mobile homes, among other things.
The gypsum board panels are conveyed through a laminator by conveyor drive belts. A major drawback of the conventional laminating process is that a shear differential exists between the gypsum panel and the conveyor drive belts. This shear differential frequently causes the plies of the gypsum board panel's backing paper layer to delaminate as the panels are conveyed through the laminator. Such delaminations are referred to as rollups. Rollups occur even more frequently when gypsum board panels are shipped to the laminating facility hot, or when laminating is performed during hot and/or humid weather. The problem of rollups is exacerbated by the fact that many facilities are located near manufactured housing plants, which are concentrated in the southern United States, a region having a relatively hot and humid climate.
After passing through the laminator, the gypsum board panels are stacked face to back, one on top of the other. As such, any rollups in the backing paper layer of one panel often cause indentations in the face of the panel upon which it is stacked. Gypsum board panels with indentations in their face are often rejected, and are unsuitable for sale. The conventional way to address the rollup problem is to discard the panels. Due to the large number of rollups currently occurring in the gypsum board panel lamination industry, a process which reduces the frequency of such rollups can result in greater efficiency in the use of the panels, and significant savings for the laminator.
Thus, it is an object of the present invention to provide an improved process for reducing rollups in gypsum board panels when the panels are laminated with a laminate.
It is another object of the present invention to provide an improved gypsum board panel which will be less susceptible to delamination of its paper layers during the lamination process.
It is yet another object of the present invention to provide an improved process for making gypsum board paper that will be less susceptible to delamination during the lamination process.